There exists a high demand in numerous industries for components made of polyamide materials. This is because these components are light and can be conceived and designed more easily than components made of steel or aluminum, in particular in the field of the motor vehicle industry.
However, plastic components present problems when it is desired to paint them.
Thus, for example, in the field of motor vehicles, there exist in particular three main methods for painting electrostatically, that is to say by movement of the particles under the influence of an electric current. The first, referred to as “inline” process, refers to a process according to which the component made of plastic is assembled on the vehicle after the latter has been subjected to degreasing and electroplating stages, followed by a drying stage. The component made of plastic and the vehicle are subsequently painted and dried by heating. The second, referred to as “online” process, refers to a process according to which the component made of plastic is assembled on the vehicle at the beginning of the process mentioned above. The plastic components
are thus subjected to degreasing, electroplating and drying stages at temperatures which can exceed 200° C. Consequently, for this type of process, it is necessary for the components made of plastic to be able to withstand higher temperatures. In a third process, referred to as “offline” process, the component made of plastic is first painted in order to be subsequently assembled on the vehicle.
When processes for painting by electrostatic deposition are used, poor adhesion of the paint to conventional plastic components is obtained. Specifically, the paint easily comes away and does not adhere or only slightly adheres to the plastic components.
In order to render plastic components suitable for being painted by a process for the electrostatic deposition of the paint, it is known to add conductive fillers to the thermoplastic matrix. However, the incorporation of these fillers has a negative effect on some properties of the plastics, such as the mechanical properties. Furthermore, the incorporation of conductive fillers significantly increases the melt viscosity of the thermoplastic matrices, rendering them unsuitable for use in certain processes for the forming of these matrices.
Thus, there exists a need to manufacture and use plastic components exhibiting excellent mechanical properties, such as good impact strength, and a good ability to be painted by a process for the electrostatic deposition of the paint.